Device for coke oven chamber pushing low in heat exchange

ABSTRACT

A device for pushing the contents of a coke oven chamber includes a pusher ram head with pusher rams mounted there behind, wherein guiding plates or aprons are mounted to a pusher ram head which avoid a simultaneous pressing-in of air into the coke oven chamber, thus preventing a non-desired cooling-off of the coke oven chamber during pushing. The aprons also prevent the pusher ram and the rearward side of the pusher ram head from excessive heat burdens. The aprons can also serve for protecting measuring devices mounted in the enclosure. The aprons can be fabricated from a heat-resistant metallic or ceramic material. The aprons or the pusher ram head can also be provided with a heat-resistant or heat-reflecting coating or with heat-resistant or heat-reflecting tiles. Also shown is a method for pushing of coke oven chambers by applying the inventive device.

The present invention relates to a device for pushing a coke cakethrough a coke oven chamber comprised of an opening on both sides.Pushing a coke cake from a coke oven chamber is carried out at the endof a coking process of a carbonization cycle. Depending on oven type andprocess technology configuration of a coke plant with varying charge bedheight, charging coal blend and temperature in a coke oven, the cokingprocess may take 16 to 192 hrs. Coke pushing is carried out from theopening of one coke oven side to the other coke oven side. As a rule, acoke car is positioned there to capture the coke cake and to carry it toa coke quenching tower. Coke pushing is usually performed with aso-called pusher ram which to this effect is carried on a car,transported to the battery to be pushed and moved by hydraulicfacilities. Upon coke pushing, the oven is again charged with coal.

Preferably the coke oven chamber is a “Non-Recovery” or “Heat-Recovery”type coke oven which utilizes the coal by-products and coking gasesderived from the carbonization process for combustion and for recoveryof the heat needed for coal carbonization. But the coke oven chamber mayalso be a conventional so-called horizontal chamber type oven whichcaptures and further processes coal by-products from the carbonizationprocess. Coking processes are run at temperatures ranging from 800 to1500° C. A substantial part of the heat is stored in the walls and oventop comprised of silica or fireclay bricks or any arbitrary refractorybrickwork. Since combustion of coal by-products in most cases is justsufficient to generate the required coking energy, it is desired to keepthe loss of heat during coke pushing as small as possible.

In coke pushing according to prior art in technology, the pusher ramhead which a pusher ram is fastened to a slide by a suitable thrustdevice through the coke oven. At its rearward end, the pusher ram isequipped with a device that can exert a force of pressure on the pusherram. On its front side, the pusher ram head, in turn, is equipped with aplate that affords protection from the enormous heat evolving from thecoke cake. During coke pushing, the pusher ram and the pusher ram headare exposed to a substantial heat burden. As a result, component partsmay get deformed or evidence a fracture in material already after ashort service life. For this reason, there is a great deal of inventionswhich describe measures to counteract a substantial heating-up of thecoke pushing device.

DE 4224491 A1 describes a device for pushing a coke oven which iscomprised of a pusher ram head and a liquid-cooled pusher ram. Thepusher ram itself is surrounded by a radiation screen which surroundsthe pusher ram at a certain distance towards the outside and which isprovided with cooling coils on its inside. A cooling medium preferablybeing water or liquid containing water flows trough the cooling coils.Supply and return of the cooling medium is realized through connectedhoses. A back-cooling is realized through heat exchangers which arelinked to the hose connections. The pusher ram can be formed by T-beamswhich for example are welded side by side. This device has a drawback inthat passing a cooling medium through it is costly and susceptible tofailures. For example, leakages in the cooling system may lead tounnoticed damage to the pushing device or coke oven chamber.

DE 840538 C describes a device comprised of a pusher ram for pushing ofcoke oven chambers which is of a box-type configuration and which is ofa multiple component structure in its interior. The pusher ram ispreferably configured in form of a T-beam. Air serving as cooling mediumstreams through the individual parts of the pusher ram, with the airbeing guided through the pusher ram in such a manner that the walls ofthe pusher ram are always flushed through in the same direction of flow.Thereby a distortion of the pusher ram is impossible. On the pusher ramproper, at the front end side, a pusher ram head is mounted which is notspecified in greater detail in the relevant patent description. Thoughthe device cools the pusher ram, it does not protect the material of thepusher ram from intensive heat radiation. Moreover, the configuration ofthe pusher ram admits substantial quantities of cold air from theenvironment into the coke oven chamber, depending on the shape of thepusher ram head.

DE 459600 C describes a device comprised of a pusher ram for pushing ofcoke oven cambers, wherein the pusher ram head is comprised of guideplates which are welded to the upper end of the pusher ram head towardsthe rearward side and which press the pusher ram head at the upper sideagainst the coke oven top. Thereby, the coke oven pushing device can beso guided that it just leans to the upper coke oven wall. This upperwall is usually thicker than the coke oven sole which is relatively thinto allow for good heat transfer from the heating flues. In this manner,damage to the sensitive coke oven chamber floor is avoided. The improvedheat retention in the coke oven chamber wall and protecting the pusherram from heat do not play any role in this teaching. Moreover, the guideplate mounted on the upper side of the pusher ram head just covers asmall part of the pusher ram. As a result, cold air from the environmentcan stream from all sides into the coke oven chamber.

Frequently, the pusher ram is fastened in the middle of the pusher ramhead, thus leaving substantial space behind the pusher ram head throughwhich cold air from the coke oven environment is pressed into the cokeoven chamber at the same time as the oven is pushed. Moreover, throughthe free space pressed behind the pusher ram head next to the pusher raminto the oven, substantial part of the heat stored in the inner cokeoven wall radiates towards the exterior. It constitutes a substantialloss of heat which must be offset again by the next coal carbonizationprocess. As a result, coal burn-off is higher and coke produced is of aninferior quality. Owing to the increased heat radiation, the pusher ramis furthermore exposed to a severe temperature burden that may lead toits deformation and which may cause it to become brittle after a shortservice life. It represents a source of hazard because the pusher rammust take-up substantial mechanical forces and loads.

Therefore, a device is being searched for which on the one hand providesprotection to the pusher ram head and to the pusher ram from hightemperatures prevailing in a coal carbonization process. On the otherhand, the desired device should also prevent cold air from entering intothe interior of a coke oven chamber that might cool off the interior ofthe coke oven chamber during coke pushing which will entail increasedcoal consumption and inferior coke quality.

This task is solved by a guiding plate mounted on the pusher ram headand provided by the present invention. A guiding plate or an apronwrapping the pusher ram almost on its entire length is mounted on thepusher ram head. Thereby, a wrapping or enclosure is provided around theentire pushing device. The space created between the pusher ram and itsenclosure can remain free. But it can also be filled-up to providebetter insulation. Glass wool or ceramic fibres are suitable for thispurpose. Owing to the enclosure, the pushing device assumes the shape ofa quad if the pusher ram head is rectangular and wrapped on all sides bythe inventive enclosure. In the interior, the pusher ram will then forma massive cylinder. The wrapping device is preferably made of atemperature-resistant material.

Owing to the guiding plates, the pusher ram is protected from hightemperatures of the coke oven chamber and more particularly from thecoke oven walls which are exposed after coke pushing. Since the thermalcapacity and the heat-up rate of the enclosure is small, a cooling-offof the coke oven chamber and more particularly of the coke oven walls islargely prevented. Cold air from the environment cannot reach to thecoke oven walls which cannot cool-off thereby either. If the interior ofthe enclosure contains an insulating filling, the coke oven walls staynearly at the same temperatures, unless coke pushing takes excessivetime.

Claimed in particular is a device for pushing the charge of a coke ovenchamber, wherein

-   -   the device is shaped as a pusher ram in form of a ram bar        comprised of an oven-side mounted pusher ram head in form of a        plate,        and which is characterized in that    -   the pusher ram head is surrounded by mounted-on rearwardly        directed guiding plates or aprons thus forming the enclosure        which has the same outer side lengths as a the pusher ram head        and the outer shape of a quad with a uniform cross-section, if        the pusher ram head is rectangular or quadratic, with the pusher        ram positioned in the interior forming a massive cylinder if it        is round in cross-section.

The pusher ram head preferably has the same cross-section as the openingof the coke oven chamber. The outer walls of the enclosure will thenexactly lean to the coke oven chamber walls so that they are completelyshielded from relatively cold temperatures of the coke oven environmentwhen pushing-out the contents of the coke oven chamber. Thereby, theprocess of coke oven pushing can also be executed under adverse weatherconditions. The aprons also protect the rearward side of the pusher ramhead and the pusher ram from high temperatures during coke pushing.

For application on coke cake pushing, the pusher ram head can berectangular or quadratic in shape. However, it is also feasible toconfigure it in a circular shape. This is particularly advantageous witha special shape of the coke oven. In principle, it is possible toconfigure the pusher ram head in any arbitrary shape if this is calledfor by an optimal process of coke pushing.

The pusher ram, too, may have any arbitrary shape and any arbitrarycross-section. In a simple configuration, the pusher ram is configuredas a massive cylinder and has a round cross-section. As the pusher ramis advantageously mounted in the middle of the pusher ram head, it formsa massive cylinder in the quad or cylinder created by the enclosure,depending on the shape of the pusher ram head. However, for fabricationof the inventive device, the pusher ram may also have any arbitraryshape. For example, it may be configured as a quad. But it may also befabricated of simple T-beams mounted on the head side. It is alsofeasible to weld T-beams together and to utilize these as pusher ramswith improved stability. Finally, the pusher rams may be arbitrarilyshaped, depending on the requirements of the coke pushing procedure.

Preference is given to a shape which the pusher ram head forms with themounted-on wrapping or enclosure, being of a uniform cross-section inlength. Thereby, the coke oven chamber walls are completely covered bythe enclosure and do not get in contact with colder ambient air.Depending on requirements exacted from the pushing procedure, it maytaper or thicken in length and vary in cross-section. For example, thismay be useful with sensitive secondary air sole floors or chambers. Theshape may also be irregularly formed if required by the coke ovenchamber shape or for an optimal thermal protection. The entire devicefor pushing including the enclosure is advantageously so shaped that theprocess of pushing-out the contents of the coke oven chamber proceeds inmanner that is as low in heat exchange as possible.

For fabrication of the inventive enclosure, the guiding plates can bemounted on all sides of the pusher ram head. Thereby, all ovens areprotected from cooling-off or cooling-down due to a simultaneouspenetration of cold ambient air when coke oven chambers are pushed.However, it is also possible to provide less than four sides of thepusher ram head with the rear-side apron, for example if the pusher ramhead is rectangular in shape. For example, the lower side of the mouldmay remain free to protect the floor of the coke oven chamber which isusually thinner and thus less robust. It is also feasible to protectonly one side of the pusher ram head with the inventive enclosure. Theaprons may differ in length if this is called for to provide an optimalprocess for coke pushing.

The aprons or guiding plates utilized to set-up the inventive enclosurecan be fabricated of a heat-resistant metallic material. But they canalso be fabricated of a ceramic material. It is also feasible tofabricate the aprons of a metallic material and to provide them with aceramic coating. Said coating may advantageously be so configured thatit reflects or mirrors the heat from the environment. Likewise, it ispossible to provide a coating comprised of a heat-reflecting layer,mentioning here a so-called “high-emission coating”, for example. Forexample, it can be integrated by way of a high-sintering temperatureprocess into the outer layers of the material. Suitable heat-reflectingmaterials particularly are inorganic metal oxides in a blend withcarbides, with chromium or iron oxides in a blend with silicon carbidesbeing mentioned as an example. An exemplary description for ahigh-emission coating is given in EP 742276 A1. A design and structureof an apron fabricated from a heat-resistant material and comprised of aheat-resistant and insulating layer for improved insulation isconsidered optimal. The heat-resistant apron can be applied as acoating, but also in form of foils or tiles.

The pusher ram and the pusher ram head are made of a material which isresistant to high temperatures prevailing in the coke oven chamber.Preference is given to a pusher ram or a pusher ram head made of amaterial highly resistant to heat in order to withstand hightemperatures prevailing in the interior of coke oven chambers. Thepusher ram head, in particular, can also be provided with aheat-resistant coating for a better protection from high temperatures.For example, this may be a coating made of ceramic material, fireclaybricks, silica or a hydraulic guniting concrete. The pusher ram, too,can be provided with such an enclosure, if required to protect thisstructural part. As a rule, however, this is not required because lowtemperatures will prevail there owing to the aprons laid around thepusher ram.

The enclosure formed by mounting the aprons around the pusher ram headmay also be comprised of additional devices which serve for controllingthe pushing procedure. For example, these may be temperature measuringfacilities or inspection sight glasses. However, the enclosure may alsobe comprised of devices which serve for improving the cokemakingprocess. Examples for such devices are insulating materials such asglass wool or ceramic fibres.

The device is also comprised of component parts which serve forfastening to a coke pusher machine or a driving device. These componentparts are preferably fastened at the end of the pusher ram. But they canalso be fastened to the end of the aprons or of the enclosure. Itdepends on the type of coke pusher machine or drive. To operate theinventive device, both mobile coke pusher machines and stationary cokepusher machines may be applied.

Finally claimed is a method that utilizes the inventive device for cokepushing. Usually the method is so configured that the coke pushingprocedure is carried out after the procedure of door opening. As a rulethis is done upon the end of a coal carbonization process which in a“Non-Recovery” or “Heat-Recovery” coke oven typically takes 16 to 192hrs. The procedure of coke pushing is then followed by a renewedcharging. As a matter of fact, the inventive device can also be utilizedto execute a cleaning if apparatus facilities let it appearadvantageous. Upon charging, the doors of the coke oven chamber areclosed and a renewed coal carbonization cycle follows next. Theinventive method is suitable for all types of coke ovens.

Moreover, the inventive device can serve for protection of measuringinstruments that may be mounted on the pusher ram to monitor the ovenstatus as well as the carbonization process and which can be protectedby the described enclosure from radiation impacts originating from theoven interior.

The inventive device is elucidated by way of four drawings, with thesedrawings just representing examples of embodiments for the design of theinventive device.

FIG. 1 shows an opened coke oven chamber in a side view in which thecoke cake is pushed by the inventive device.

FIG. 2 shows an inventive device for pushing in a vertical view fromabove.

FIG. 3 shows an inventive device with a pusher ram composed of twowelded T-beams in a vertical view from above.

FIG. 4 shows a coke oven chamber during the procedure of coke pushingwith an inventive device in a front view.

FIG. 1 shows an open coke oven chamber (1) in which the coke cake (2) isexposed upon opening of the coke oven chamber doors (3). The coke cake(2) is pushed with the pusher ram head (4) of the coke pushing devicefrom the coke oven chamber. For this purpose, the pusher ram head (4)together with the pusher ram (5) is pushed through the coke oven.Rearwardly directed aprons (6 a) are fastened to the pusher ram head(4). If the pusher ram head is rectangular, only the upper and lowerapron can be seen in this view. The lateral aprons (6 b) were omittedfor better elucidation. Since cold air would be pressed into the cokeoven chamber unless aprons are mounted behind the pusher ram head, theseaprons prevent a cooling-off of the coke oven chamber. The pusher ramhead is advantageously so shaped that it fits exactly between thedoor-encompassing coke oven chamber wall (7) and coke oven sole (8).Thereby an admission of further air from outside is prevented. Usuallylocated under the coke oven sole are the secondary air soles (9) and thesecondary air inlet devices (10) so that the floor can be a bit thinner.Also shown here are the primary air inlet devices (11) in the ceilingwith control devices (11 a) and rope tackles (12) to actuate the doorwith fastenings (12 a).

FIG. 2 shows an inventive pushing device comprised of a pusher ram head(4) and a pusher ram (5). Fastened to it are the aprons (6 b) which forman enclosure. If the pusher ram head is rectangular, only the lateralaprons can be seen in this view. A fastening for the coke pusher machine(13) still follows next to the pusher ram.

FIG. 3 shows an inventive pushing device with a pusher ram head and apusher ram. The pusher ram head (4) and the pusher ram (5) are formed oftwo T-beams welded together. To be seen here are the lateral aprons.Applied on the pusher ram head is a layer (14) composed of a materialwhich is highly resistant to heat.

FIG. 4 shows a coke oven chamber (1) in a front view, whose coke cake(2) is pushed-out with an inventive device. The coke oven chamber isopened through the pulled-up coke oven chamber doors (3) so that thecoke cake (2) is exposed. The coke oven chamber wall (7) encompassingthe door is concealed here by the pulled-up coke oven chamber door (3)and therefore it cannot be seen. The pusher ram head (4) advantageouslyhas a cross-section which exactly fits into the opening so that the cokecake (2) lies behind the pusher ram head (4). The pusher ram head (4) ispushed out from the coke oven chamber by the aid of pusher rams (5). Thepusher ram head (4) is equipped with aprons which are mounted inrearward direction (protruding from the plane of paper). Here the pusherram head is rectangular so that both horizontal ((6 a) and vertical (6b) aprons are fastened. The aprons prevent cold air from entering intothe coke oven chamber behind the pusher ram head (4). To be seen here,too, are the secondary air soles (9), the openings for secondary air(10), the openings for primary air (11) in the oven top with controlfacilities (11 a) and rope tackles (12) to pull-up the coke ovenchambers doors including the fastening (12 a).

LIST OF REFERENCE SYMBOLS

-   1 Coke oven chamber-   2 Coke cake-   3 Coke oven chamber door-   4 Pusher ram head-   4 a Weld seam-   5 Pusher ram-   6 a Horizontally mounted apron or enclosure-   6 b Vertically mounted apron or enclosure-   7 Oven wall encompassing the door-   8 Coke oven chamber sole-   9 Secondary air sole-   10 Access openings for secondary air-   11 Access openings for primary air in the ceiling-   11 a Control facility for primary air-   12 Chain or rope tackle to open coke oven chamber doors-   12 a Fastening of the door to the rope tackle-   13 Fastening of the coke pusher machine to the pusher ram-   14 Heat-resistant layer

1-23. (canceled)
 24. A device for pushing the charge of a coke ovenchamber, wherein the device is shaped as a pusher ram in the form of aram bar comprising an oven-side mounted pusher ram head in form of aplate, wherein the pusher ram head is surrounded by mounted-onrearwardly directed guiding plates or aprons thus forming the enclosurewhich has the same outer side lengths as the pusher ram head and theouter shape of a quad with a uniform cross-section, if the pusher ramhead is rectangular or quadratic, with the pusher ram positioned in theinterior forming a massive cylinder if it is round in cross-section. 25.The device as defined in claim 24, wherein the pusher ram head has around shape so that the device for pushing has the outer shape of acylinder with a uniform cross-section.
 26. The device as defined inclaim 24, wherein the pusher ram head has any arbitrary shape so thatthe device for pushing has the extended outer shape of the cross-sectionof the pusher ram head.
 27. The device as defined in claim 24, whereinthe cross-section of the enclosure varies in the rearwardly directedcourse so that the enclosure has any arbitrary shape.
 28. The device asdefined in claim 24, wherein the aprons are shorter in length than thepusher ram.
 29. The device as defined in claim 24, wherein the aprons onthe sides of the pusher ram head differ in length.
 30. The device asdefined in claim 24, wherein the pusher ram has a round cross-section ofany arbitrary shape and is cross-section-wise positioned in the centerof the pushing device.
 31. The device as defined in claim 24, whereinthe pusher ram has any arbitrary cross-section of any arbitrary shapeand is cross-section-wise positioned at any arbitrary position of thepushing device.
 32. The device as defined in claim 24, wherein thedevice for pushing the contents of a coke oven chamber has exactly thecross-section of the opening of the coke oven chamber to be pushed orcharged, respectively.
 33. The device as defined in claim 24, whereinthe aprons are mounted on all sides of the pusher ram head.
 34. Thedevice as defined in claim 24, wherein the aprons are mounted on lessthan all sides of the pusher ram head.
 35. The device as defined inclaim 24, wherein the pusher ram for pushing-out the coke cake is aT-beam.
 36. The device as defined in claim 24, wherein the pusher ramfor pushing-out the coke cake is a pusher ram comprising several T-beamswelded together.
 37. The device as defined in claim 24, wherein theenclosure is wholly or partly made of a heat-resistant metallicmaterial.
 38. The device as defined in claim 24, wherein the enclosureis wholly or partly made of a heat-resistant ceramic material.
 39. Thedevice as defined in claim 24, wherein the pusher ram at the pusher ramhead or on the enclosure or at the pusher ram head and on the enclosureis provided with a coating made of a heat-protecting material.
 40. Thedevice as defined in claim 39, wherein the coating made of aheat-protecting material is applied in form of foils or tiles.
 41. Thedevice as defined in claim 39, wherein the coating is applied as ahigh-heat reflecting layer in form of a “high-emission” coating.
 42. Thedevice as defined in claim 41, wherein this coating comprises inorganicmetal oxides blended with carbides.
 43. The device as defined in claim24, comprising facilities positioned in the interior of the shape formedby the enclosure to measure the temperature.
 44. The device as definedin claim 24, comprising insulating materials positioned in the interiorof the shape formed by the enclosure.
 45. The device according to claim44, wherein the insulating materials are glass wool or ceramic fibres.46. A method for carbonization of coal comprising: providing a pushingdevice as claimed in claim 24; and applying the device to push the cokein a coke oven chamber.